unr2-t221 Riedon Powertron, unr2-t221 Datasheet - Page 2

• Manufacturer Part Number: unr2-t221
• Description: Precisionfoilresistors
• Manufacturer: Riedon Powertron

Riedon Inc.
USR UNR
USS UNS
Precision Foil Resistors
120
100
Dimension
80
60
40
20
0
25
A
B
C
D
E
F
G
H
K
USS 2-T220 / UNS 2-T220
J
I
-200
-400
-600
-800
800
600
400
200
Temperature of the backplate(°C)
2-T220
0
2-T220 / T220B / T221
50
300 Cypress Avenue
12.70
10.16
14.60
15.00
17.33
0.76
5.08
4.00
1.20
0.40
1.85
mm
-5ppm/K
85
-50
100
(±mm)
tol.
0.2
0.2
0.1
0.1
0.1
0.1
0.2
0.2
0.2
0.1
0.1
-25
115
SPECIFICATIONS
inches
130
0.50
0.40
0.03
0.20
0.16
0.05
0.57
0.59
0.68
0.02
0.07
Temperature Coefficient
0
145
Alhambra CA 91801
www.riedon.com
(±inches)
Temperature (°C)
0.008
0.008
0.004
0.004
0.004
0.004
0.008
0.008
0.008
0.004
0.004
Dimensions
tol.
25
155
Derating
50
Power Rating Notes -
The U-Series Resistors must be attached to a suitable heatsink.
The maximum internal resistor temperature is 155°C.
To specify an appropriate heatsink use the following formula :
R
Where: R
(continued)
75
qH
= T
P
MAX
100
R
T
T
P = Power Through Resistor ( W )
Dimension
A
MAX
[phone]
qH
qR
= Ambient Temperature of Heatsink ( °C )
- ( P x R
= Thermal Resistance of Heatsink ( K/W )
= Thermal Resistance of Resistor ( K/W )
= Maximum Temperature of Resistor
C
D
A
B
E
F
125
qR
12.10
18.33
) - T
11.16
5.08
1.76
3.20
mm
A
Nominal Spread
±2.3ppm/K
Nominal ∆R/R
Nominal Spread
±2.3ppm/K
+5ppm/K
inches
0.476
0.439
0.722
0.200
0.069
0.126
[phone]
Page 125
rev. 03/2006A